A small but growing body of research has begun to identify the consequences of military service during the all-voluntary era. In this article, we examine the relationship between military service and the likelihood that cohabiting unions will be converted into marriages. Our paper extends previous research by making a distinction between the effects of active-duty verses reserve-duty service on the transition to marriage using data from the 1979-2004 National Longitudinal Survey of Youth (NLSY). Our findings indicate that there is a positive relationship between active-duty service and cohabitors transitioning to marriage.